1. Field of the Invention
The invention relates to wireless remote pen-based data terminals and to methods for their use. More particularly, the invention relates to a portable pen-based computer which is coupled by a wireless network to a host computer which supplies the portable computer with data and with forms such that data and drawings can be entered by a stylus on the forms and stored in the host computer. The invention is particularly well suited for medical applications such as entering and retrieving patient information.
2. State of the Art
Remote data entry and retrieval is ubiquitous in all phases of modern life from business and industry to education and entertainment. In its basic form, a remote computer or terminal is coupled to a host computer through a digital network or modem connection. The host computer generally provides the terminal with menus and/or a graphical interface through which information may be exchanged. Information is entered or retrieved by a remote terminal using a keyboard and/or a mouse.
Despite the widespread use of computer terminals for the entry and retrieval of information, paper forms and pens are still necessary for the collection of information in many situations. The primary reasons why information is still collected in this way include portability, ease of use, and independence from electrical power requirements. For example, in the medical profession, which is otherwise technologically quite sophisticated, information on patients is routinely collected by nurses and physicians using pre-printed paper forms and pens. This information is then later transcribed by clerks using computer terminals so that the information can be stored for later retrieval.
Portable computers and modern operating systems have alleviated the need for paper data entry in some areas. Recent developments in nickel metal hydride (NiMH) battery technology have expanded the useful life of portable computers to eight hours or more between charges. In addition, graphical user interfaces have eliminated the need to learn arcane commands in order to use a computer. Yet, while it is ultimately more efficient to enter data directly into a computer, it is still often much easier to collect data using a pen and paper. This is particularly true when the person collecting the data is travelling from one location to another, such as a doctor visiting patients in an office or hospital. A portable computer must be placed on a flat surface or the user's lap and generally requires the use of both hands and a minimum typing skill. The computer is therefore not nearly as convenient as holding a clipboard or note pad in one hand and a pen in the other whereby notes may be made quickly and easily.
Recently, small portable pen-based computers have been introduced. Pen-based computers are capable of connecting with a host computer through a wireless network. Pen-based computers typically do not have a keyboard or a mouse. They provide a position sensitive LCD display and a stylus for touching locations or writing or drawing on the display. Menu items displayed on the position sensitive display can be selected by pressing the display with the stylus at the location on the display where the menu item appears. Some pen-based computers such as the APPLE NEWTON MESSAGE PAD and the AT&T EO attempt handwriting recognition, although the accuracy of handwriting recognition technology is quite variable. Typically, the user must develop a clear and consistent handwriting style in order for the pen-based computer to recognize the handwriting as coded text. It typically takes from several hours to several weeks to train the computer to recognize the handwriting of a particular user, after which time the computer is "personalized" to that particular user. Most users are unwilling or unable to provide sufficiently clear and consistent handwriting or to take the time necessary to train the computer or tho have the computer train the user to write neatly and consistently. Some pen-based computers may optionally not attempt to recognize handwriting, but instead store the handwriting as "electronic ink". Electronic ink can presently be saved, for example, in a standardized file format called JOT which is a type of graphic file format that does not interpret the meaning of the handwriting but only saves the sequence of stylus strokes of the handwriting. The advantages of saving handwriting as electronic ink are that there is no loss in accuracy by attempting to convert it to typed text and the user does not need to train the computer. One of the disadvantages of saving handwriting as electronic ink, however, is that electronic ink remains unintelligible to a computer and the information contained in the handwriting cannot be related to other information by the computer. Electronic ink, though, may be processed at any later time by more powerful handwriting recognition algorithms than may be resident on a pen computer, or which have yet to be developed.